Farmers frequently plant crops in fields that have debris and waste material covering the field. Such material may consist of straw or old crops, which is frequently referred to as trash. In order to plant seeds or deposit fertilizer in such fields, coulter assemblies are tools that are used to create furrows or seed trenches in the soil. These coulter assemblies are typically attached, in a side-by-side configuration, to a frame which is then pulled behind a tractor to create a slot that allows the injection of agents, such as fertilizer and seed, into a field.
One problem that may occur with known coulter assemblies is an accumulation of dirt and debris between the discs and the struts as they rotate through the soil. If the soil is wet, it may stick and build up on the discs, which can inhibit rotation of the discs, cause poor disc penetration, excessive soil disturbance and create excessive draft forces. Conventional scrapers are made of steel and tend to wear relatively quickly and require a high scraper pressure when used in heavy, wet, clay soil. Once the scraper wears, the contact area between the scraper and the disc increases, further increasing the spring force that is required to keep the scraper in contact with the disc to keep the disc clean, which consequently increases the drag force on the coulter assembly. Moreover, if the field consists of sections of clay and sandy soil, the coulter assembly has less frictional force available to turn the coulter disc when it is pulled through the sections of sandy soil. The high spring force on the scraper blade may cause difficulties since the disc may stop turning when pulled through the sections of sandy soil, thereby causing operational problems.
In U.S. Pat. No. 493,182 issued Mar. 7, 1893, Platt teaches the use of a rod, which rotates freely about a spool between discs, to break up clogs of dirt and debris which form as the coulter discs create a furrow. The rod drags behind the discs and as soil accumulates, the rod rotates upward until the rod is stopped above the discs. The rod breaks the soil clumps which fall beside the disc. A scraper blade is also provided which is subject to a spring force to keep the scraper blade in contact with a surface of the coulter. As the coulter disc rotates, the scraper blade maintains contact with the surface to remove debris.
In U.S. Pat. No. 5,626,196 issued May 6, 1997, Hughes teaches the use of a blade which continuously contacts the surfaces of a coulter disc to scrape the disc and clean it as the disc rotates. In an embodiment, the scraper blade is made of plastic to permit flexibility, as it also bends when in contact with the soil. This scraper blade performs the dual role of acting as a scraper/cleaner and also as a closer. Once the disc opens a furrow in the soil, the scraper blade acts as a closer since it will force some of the soil back into the furrow after seeds have been deposited.